Boil hen until tender in water seasoned with onion, celery, salt & pepper. Cut chicken into bite size pieces and reserve all stock. Chop onion & bell pepper. Combine soups & grated cheese. Just before putting casserole together, soak the frozen tortillas in boiling chicken stock until wilted, (one at a time). Start layering casserole in 9 x 12 dish. Layer tortillas "dripping with stock", chicken, onion, bell pepper, sprinkle to taste with chile powder & garlic salt, soup mixture and cheese. Repeat the layers, being sure the tortillas are oozing with stock. Cover casserole with Rotel & its juices. Juices in dish should be about 1/2 the depth of the dish; if not, add a little more stock. Bake uncovered at 375 for 30 minutes. Make at least one day ahead & refrigerate before baking. Can be frozen before baking. Serves 8 to 10.